This invention is directed to improvements in a door frame system for a sliding door construction of the type used for barns or similar structures. The invention is directed to improvements of the door construction as a whole, as well as to various novel component features thereof.
Sliding door constructions for relatively large doors such as are used in barns or similar buildings are well known in the art. In addition to barns, such buildings generally include commercial or industrial buildings, which may take the form of a rigid framework structure covered with a suitable siding, often of aluminum or similar materials. While many advances have been made in the construction of such buildings, there remains room for improvement in the laterally sliding doors commonly provided for such structures. In this regard, such doors are generally relatively large to provide of ingress and egress of large vehicles, livestock, or the like.
A number of problems have arisen with sliding door constructions heretofore in use. Such door constructions, in similar fashion to the buildings mentioned above generally comprise a framework of wood, metal or other material upon which a "skin" or covering of siding, often of aluminum, is attached. Such sliding doors are subject to damage and deformation from a variety of sources when in use. For examples, vehicles, livestock or other objects moved through the doors may inadvertently collide with the door causing damage or deformation to portions of the skin, to the frame or both. Additionally, wind damage is frequently encountered. In this latter regard, in view of the relatively large size of such doors, sudden gusts of wind may dislodge the doors from the track or tracks generally provided therefor. Such wind damage may also cause deformation or damage to the skin, to the frame or both in cases where the door is inadequately supported by the tracks or other support structures.
Heretofore, repair of such damage has proven relatively difficult and expensive. In most door constructions heretofore provided, repair of even relatively minor damage such as bent or deformed frame sections has usually required removal of the door structure from the building. Thereupon, the door must be extensively disassembled to effect replacement or repair of the damaged part or parts, then re-assembled and remounted to the building. Additionally, the door structures heretofore provided have generally comprised a number of differently configured frame members of differing lengths as generally required to provide vertical sides or uprights, horizontal top and bottom frame members and one or more intermediate support members. Hence, in order to construct or repair such door structures, the contractor or supplier firm had to stock a large inventory of different frame components of varying lengths, in an effort to accommodate anticipated future construction and repair requirements. Needless to say, this has proven most difficult and expensive from a standpoint of inventory maintenance and control.
As an additional matter, sliding door constructions heretofore provided have frequently encountered difficulties in operation once installed on a building. In particular, track or guide members have generally been provided at the top and bottom surfaces of the assembled doors. The bottom track or guide usually comprises an open channel member for slidably receiving a bottom edge of the door. In operation this channel frequently becomes clogged with dirt, gravel or other debris, making opening and closing of the sliding door difficult or impossible. Moreover, it has been found that these bottom guide channels become filled and clogged with snow and ice quite readily, even with but a minimum snowfall. Such clogging, from whatever source, impedes or prevents sliding of the door for opening and closing.
Top guide members heretofore provided have generally consisted of a wheeled "truck" assembly from which a top portion of the door is suspended, which truck rides in a track attached to the building above the top of the door. This suspended operation has proven generally satisfactory in most instances. However, the phenomena known as "lifting" of the door in response to sudden gusts of winds has been encountered in many instances. Such "lifting" phenomena tend to lift the entire door assembly, often releasing it from its bottom track or guide members even when the door is in a fully open or fully closed position. A related wind problem is that of twisting or torque forces applied to the door, which may also cause severe distortion of the door frame or siding or both if the door is not adequately supported. This latter wind damage often occured even when the door constructions heretofore provided are in fully open or fully closed positions.
As an additional matter, reliable positive latching and unlatching of such sliding door constructions from the outside of the building has rarely been provided heretofore. Many such constructions require additional access doors to the building for the purpose of manipulating various latching and closure assemblies located on the inside of the sliding door structures. In this regard, particular difficulty has heretofore been encountered in achieving satisfactory latching and support when the doors are closed for protection from wind damage in constructions in which sliding doors are provided in pairs. The doors of such a pair usually meet or butt up against each other substantially at a center of a doorway when in the closed condition and slide laterally oppositely to overlie opposite adjacent sides of the building when in the open condition.